Note we hear for singer (5)
I believe the answer is:
tenor
'for singer' is the definition.
(tenor is a kind of singer)
'note we hear' is the wordplay.
'note' becomes 'tenner' (a ten pound sterling bank note).
'we hear' indicates a 'sounds like' (homophone) clue.
'tenner' is a homophone of 'TENOR'.
(Other definitions for tenor that I've seen before include "General meaning of a male voice" , "High voice - low bell" , "Male singer with high register" , "General drift or meaning" , "Pavarotti, for example" .)